less cardio and more weights - does it help in weight loss?

Eat in a deficit. Do cardio you like. Lift weights. The scale number may slow down, but you'll be happier with the results. You'll retain muscle while eating in a deficit as you lose if you lift. If you do cardio only, you'll lose muscle along with fat. Don't just rely on the scale, take photos and measurements as well.

In addition to the above advice, read the first post in this forum, "Most Helpful Posts".

There is no point in lifting weights for a short period, or without some plan. If increasing strength and/or building muscle interests you, weight lifting will help, but not in a few weeks.
As for losing weight, you lose weight by eating less than you burn. Whether this just mean eating less or adding calorie burning activities or anything in between it is up to you.
Since you are still very young and you say you have lost weight before (and I assume gained it back) I would suggest you stop thinking of this as a short term plan (eat/not eat this or that, do X or Y exercise for the next weeks) and start to think of it as a change in habits. Find a way to change your eating gradually, either by making better food choices or by reducing portions, and find an exercise routine you love and will stick to it, not one that promises fast results.

I got a trainer (since nothing else has worked) and its been three months seeing him once to twice a week and while I have lost any weight (muscle is heavier than fat) I LOOK so much leaner and better. I have more control over my body, feel more empowered. I have greater flexibility, and my body is burning more calories and fat at rest because its fueling the muscle I'm building! So, stick with it. Every trainer I've spoken with say diet and weights to lose weight.